Not sure about Win 7, 64... but I have my new HTPC coming in 9 days and can let you know. I just ordered a complete Microsoft remote and IR set on Ebay (listed at $19.99). FYI, I put in an offer (which was accepted) for $14. Add in shipping and you get a complete microsoft remote IR kit (remote, receivers, IR receiver extensions, and component video to Svideo converters) for <$20 (only catch is it has American and Japanese characters), though I will not actually be using the remote most of the time, I got it for the same price at which the IR receiver ONLY is listed by itself.
If you are interested, try making an offer... may even be able to get the kit for $10-13 and the receiver only for even less ($7-8 + s&H?).
http://cgi.ebay.com/Microsoft-Window-Media-Center-Vista-7-Remote-Control-IR_W0QQitemZ200406095417QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2ea9225639
The same seller has a microsoft/dell IR receiver only for sale as well: but note that this one does NOT come with "two IR receiver extensions, and two component video to Svideo converters" whereas the above product/link does.
http://cgi.ebay.com/Microsoft-Media-Center-Keyboard-Remote-IR-RC6-Receiver_W0QQitemZ200406092746QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2ea9224bca
Let me know how you make out...